A.T. Robertson Commentary Matthew 26:43

"And he came again and found them sleeping, for their eyes were heavy." — Matthew 26:43 (ASV)

For their eyes were heavy (ησαν γαρ αυτων ο οφθαλμο βεβαρημενο). Past perfect passive indicative periphrastic. Their eyes had been weighted down with sleep and still were as they had been on the Mount of Transfiguration (Luke 9:32).